Differential gear for self-propelling vehicles.



. 1 Patented July 29, I902. A. HERSCHMANN. DIFFERENTIAL GEAR FOR SELFPBOPELLING VEHICLES.

(Applicfition flled' June 21, 1901.)

2 sheets-sheet I.

(No Model.)

WITNESSES fiaM MA cams PETERS co. Puma urn. WASNINGTON o c Na. 70557:. vPatented July 29,1902.

A. HEBSGHMANN. DIFFERENTIALfGEAR FOR SELF PRDPELLIP IG VEHICLES.

\No Model.)

. (Application filed June 21, 1901.)

2 Sheets-Sheet 2,

WITNESSES-i m: Mums PETERS ca, vuoromua. msmnmou. u, c.

UNITED STATES PATENT OFFICE.

ARTHUR HERSCHMANN, OF NEW YORK, N. Y.

DIFFERENTIAL GEAR FOR S ELF -PROPELLING VEHICLES.

SPECIFICATION forming part of Letters Patent No. 705,671, dated July 29,1902.

: Application filed June 21,1901. Serial No. 65,387. (No model.)

To all whom (it may concern.-

Be it known that I, ARTHUR HERSOHMANN, a subject of the Emperor'ofAustria-Hungary, residing at the city of New York, in the borough ofManhattan and State of New York, have invented certain new and usefulImprovements in Differential Gear for Self-Propelling Vehicles, of whichthe following is a full, clear, and exact description.

This invention relates to compensating or diiferential gear forself-propelling vehicles,- the object of the invention-being 'to providemeans whereby when the necessity arises for rotating both traction-'wheels at the same speed, notwithstanding the fact that they may beacting under different tractive forces, the compensating gear can belocked so that the two parts of the shaft may travel together. Itsometimes happensthat with onetractionwheel of a loaded truck in agutter or depression of the road and the incline of the vehicle throwingthe load toward the low wheel and away fromthehigher wheel and the latter possibly resting upon a slippery portion of the road the full rotaryeffect of the motor is taken up by the lightly-loaded wheel, which willspin around, while the other wheel will remain stationary, thuspreventing the vehicle from moving. Under such conditions it isdesirable to lock the compensating-gear or throw it out of action, sothat the two parts of the shaft which drives the traction-wheels areconnected together as one solid shaft and the rotary effect and power ofthevmotor applied equally to both traction-wheels, which will result inmoving the vehicle under the conditions named.

The invention will be described with reference to the accompanyingdrawings, in which- Figure 1 is ase ctional view of an ordinary form ofcompensating gear having my improved device applied thereto. Fig. 2 is aside elevation of the same, and Fig. 3 illus trates the system of leversfor operating the lock. Fig. & is a section of apart of the compensatinggear and lock.

The two parts of the driving-shaft are indicated by a and a,respectively. Their abutting ends are surrounded by a common form ofcompensating or diiferential gear used for the purpose of allowing onewheel to turn at a different speed from the other. This gear consists ofa drum B, loosely mounted on the hubs of two bevel gear-wheels c and c,which are keyed to the respective shafts and face each other inside ofthe drum. The drum carries on its periphery the gearteeth b,with whichthe engine-pinion engages, and is provided with one or more radialshaftsb in the nature of spokes which are fixed at their outer ends insuitable bossesin the rim of the drum and at their inner ends in a hub17*, surrounding the abutting ends of the shaft. On these radial shaftsare loosely mounted bevel-pinions 6, each of which gears with both ofthe bevel-gears c and c. In this construction, which is quite ordinary,as before stated, the two parts of the shaft will rotate at the samespeed when the power is applied to either one of them, provided thetractive force of both wheels is the same; but when the tractive forcediifers one wheel is allowed to turn faster than the other, thedifference in motion being provided by the rotation of the pinions e ontheir shafts, al-

lowing one of the gears c to move ahead of the other.

In accordance with my invention I provide one of the gears c or c with aflange 0 in which are formed at intervals the notches c At a convenientpoint inthe drum I locate a shaft f, having its hearings in the sides ofthe drum, preferably near the periphery, and extend one end of the shaftoutside of the drum, where it is provided with a lever g, rigidlysecured thereto and having two notches g in its outer end. This lever isin a plane parallel to the side of the drum and close to it and isadapted to rest against either of .two stop-pins s and s and be held inthose positions by a spring g the end of which engages one or the otherof the notches g. Inside of the drum the shaft f carriesa pawl or dog2', which is located in the plane of the flange 0 This pawl being alsotighten the shaft is adapted to be thrown toward and away from theflange by rocking the shaft, which motion will cause it to engage ordisengage with one of the notches in the flange of the gear-wheel. Forobtaining this movement of the dogI provide the leverg with an extensiong projecting beyond the periphery of the drum a slight distance, and ona suitable part of the frame of the vehicle I pivot a lever h, carryinga stop-block h, adapted to be thrown into and out of the path of theextension 9 by means of a system of levers 5 j, operated by the driverof the vehicle by stamping on a footpiece j.

The operation of the device is as follows: Then the driver finds thatthe vehicle is stalled by reason of one of the tractionwheelsabsorbingall of the rotary effect of the engine or motor due to onewheel being in a rut and the other on slippery ground or to any othercause, he will slow down the engine and then stamp on the footpiece j,and thus throw the block it toward the drum and into the path of theprojection 9 The projection will then strike the block, the lever g willbe tilted, -and the pawl 71 carried against the flange and into one ofits notches,the pawl being held in this notch by the spring 9 engagingwith the lever g. The drum, the wheels 0 and c, and the pinions e arethen all locked together. In order to disengage the block h from theprojection 9 the engine must be reversed and given a partial turn,whereupon a spring connected with the levers j will return the block toits normal position. Then the engine is again reversed and all parts,including both sections of the shaft, are driven together and thevehicle is propelled out of its stalled position. When the conditionsare again normal, the engine is reversed, and the block h again throwntoward the drum to allow the projection g to strike its opposite side.This reverses the position of lever g and withdraws the pawl from thenotch in flange c and allows the compensating gear to perform its usualfunction, after which the engine can again be sent ahead.

Having described my invention, I claim- 1. In a vehicle, the combinationof a shaft in two parts, two traction-wheels driven respectively by thesaid parts, a compensating gear interposed between the parts, means forlocking the parts of the compensating gear together to thereby destroyits compensating function and means for controlling said looking meansfrom a distance.

2. The combination of a shaft in two parts, a bevel-gear fixed upon eachpart, a concentric drum adapted to be driven, a radial shaft supportedby said drum, a pinion on said radial shaft said pinion being in meshwith both of said bevel-gears, one of said bevel-gears having a notchedflange, a pawl carried by the drum and means for causing said pawl toengage and disengage the notches in said gear.

3. The combination of a shaft in two parts, a bevel-gear fixed upon eachpart, a concentric drum adapted to be driven, a radial shaft supportedby said drum, a pinion on said radial shaft said pinion being in meshwith both of said bevel-gears, one of said bevel-gears having a notchedflange, a shaft mounted in said drum, a pawl on said shaft adapted toengage with said flange, a lever on said shaft and means for throwingthe lever, for the purpose set forth.

In witness whereof I subscribe my signature in presence of twowitnesses.

ARTHUR IIERSOHMANN.

\Vitnesses: WM. A. ROSENBAUM, WALDoM. CHAPIN.

